Biomimetic Diamond-like Carbon Coating on a Lumen of Small-diameter Long-sized Tube Modified Surface Uniformly with Carboxyl Group using Oxygen Plasma

Silicone tubing is used in small-diameter long-sized tubes for medical applications, such as urinary catheters. However, bacteria in urine adhere to the catheters, forming colonies and biofilms and resulting in blockages and urinary tract infections. Therefore, we have reported a method of AC high-voltage plasma chemical vapor deposition to prevent bacterial adhesion by depositing diamond-like carbon (DLC) on a lumen of a silicone catheter and smoothing the surface. However, the sp3/sp2 structure of DLC on the lumen surface is unresolved, and biomimetic DLC with a functionalized surface has not been investigated. Therefore, we analyzed a flexible membrane structure that can deform as the resin tube deforms. In addition, we developed a lumen surface-modification method using an AC high-voltage burst oxygen plasma processing to bring the DLC surface closer to the in vivo environment. We succeeded in creating biomimetic DLC and introducing carboxyl groups. Using this technology, the surface functionalization of medical tube materials is biocompatible with various protein-adsorption properties.